810 patients from 30-40 centers in North America and Europe will be entered in a randomized, stratified, parallel-group, double-blind trial comparing placebo with two doses of SR 57746A in individuals aged 18-75 years with a diagnosis of ALS. There will be 13 visits over 18 months. There is no cure for ALS. The only approved treatments is Riluzole and if individuals wish to take Riluzole they may be followed in a separate study. Patients will continue to be followed in the Washington University Neuromuscular clinic for their regular medical/ALS care.